Partial interface should use original interface's cpp_name.

Source/bindings/scripts/interface_dependency_resolver.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 167 matching lines @@
             # - A partial interface defined in core cannot update
             #   the original interface defined in modules.
             if not is_valid_component_dependency(dependency_component, component):
                 raise Exception('The partial interface:%s in %s cannot update '
                                 'the original interface:%s in %s' % (dependency_interface.name,
                                                                      dependency_component,
                                                                      target_interface.name,
                                                                      component))
 
             if dependency_component in resolved_definitions:
+                # When merging a new partial interfaces, should not overwrite
+                # ImpelemntedAs extended attributes in merged partial
+                # interface.
+                # See also the below "if 'ImplementedAs' not in ... " line's
+                # comment.
+                dependency_interface.extended_attributes.pop('ImplementedAs', None)
                 resolved_definitions[dependency_component].update(dependency_definitions)
                 continue
 
             dependency_interface.extended_attributes.update(target_interface.extended_attributes)
             assert target_interface == definitions.interfaces[dependency_interface.name]
+            # A partial interface should use its original interface's
+            # ImplementedAs. If the original interface doesn't have,
+            # remove ImplementedAs defined in the partial interface.
+            # Because partial interface needs the original interface's
+            # cpp class to obtain partial interface's cpp class.
+            # e.g.. V8WindowPartial.cpp:
+            #   DOMWindow* impl = V8Window::toImpl(holder);
+            #   RawPtr<...> cppValue(DOMWindowQuota::webkitStorageInfo(impl));
+            # TODO(tasak): remove ImplementedAs extended attributes
+            # from all partial interfaces. Instead, rename all cpp/header
+            # files correctly. ImplementedAs should not be allowed in
+            # partial interfaces.
+            if 'ImplementedAs' not in target_interface.extended_attributes:
+                dependency_interface.extended_attributes.pop('ImplementedAs', None)
             dependency_interface.original_interface = target_interface
             target_interface.partial_interfaces.append(dependency_interface)
             resolved_definitions[dependency_component] = dependency_definitions
         else:
             # Case: target_interface implements dependency_interface.
             # So,
             # - An interface defined in modules can implement some interface
             #   defined in core.
             #   In this case, we need "NoInterfaceObject" extended attribute.
             # However,
@@ skipping 76 matching lines @@
         for key, value in extras.items():
             if key not in attributes:
                 attributes[key] = value
 
     for attribute in dependency_interface.attributes:
         update_attributes(attribute.extended_attributes, merged_extended_attributes)
     for constant in dependency_interface.constants:
         update_attributes(constant.extended_attributes, merged_extended_attributes)
     for operation in dependency_interface.operations:
         update_attributes(operation.extended_attributes, merged_extended_attributes)